Explanation:

- Option 1: Plato

- Ancient Greek philosopher.

- Mainly focused on political theory and the ideal state.

- Did not systematically formulate the doctrine of separation of powers.

- Option 2: Montesquieu

- French political philosopher.

- Developed the modern concept of separation of powers.

- His work "The Spirit of the Laws" detailed this doctrine, influencing many democratic constitutions.

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- Option 3: Dicey

- British jurist.

- Known for his work on constitutional law and the rule of law.

- Did not formulate the doctrine of separation of powers.

- Option 4: Aristotle

- Ancient Greek philosopher.

- Analyzed different forms of government.

- Discussed concepts of governance but did not systematically develop this specific doctrine.